GCSE Ecosystems and material cycles Biodiversity: A large sum of money is spent annually on maintaining local and global biodiversity. Is this a good use of money? Explain. Why is a high biodiversity important in ensuring the stability of ecosystems? Explain the conflict which exists between the need for cheap compost, food security and the destruction of peat bogs. Why are compost bins not air tight? Does garden waste decay in the winter? Field work: Is random sampling really random when sampling an area with a quadrat to find the abundance of daisies in a field? Lichens are an indicator species. What environmental change do they indicate? How accurate would a conclusion about the level of pollution in an environment be if the presence or absence of blackspot fungus on roses was used as an indicator? Research the holly leaf miner. Construct a food chain starting with the holly leaf. How materials are cycled: Are plants actually primary consumers of carbon dioxide? How does the ocean carbon cycle compare to the carbon cycle on land? Explain how carbon is recycled into new growth in a plant when the leaves fall to the ground. Plants take in mineral ions through their roots by active uptake. Are there less minerals in a woodland compared to a patio covered garden? Interdependence: “Denitrifying bacteria are useless”. Do you agree with this statement? Explain. “In the natural world, no organism is cut off from its surroundings”. Choose an ecosystem and explain this statement. The Global Seed vault is an expensive way of storing seeds. Why is it globally important and why was the Arctic chosen as the main repository? If a gardener buys ladybirds as a method of biological control, does this destabilise the ecosystem? Ecosystems: Describe the importance of interdependence and competition in a named ecosystem. Bladder wrack seaweed has air bladders. Why? Grey squirrels have driven out native red squirrels from most areas in England. Does it matter? Explain your answer. Psychrophiles are examples of extremophiles. Where do they live and what are the challenges? Explain why a stable community undergoes cycles of rising and falling in number of predators and prey. Edexcel GCSE Ecosystems and material cycles ThinkIT! © Copyright The PiXL Club Ltd, 2017 Food security (biology): The increase in demand for palm oil has driven up global food prices. Explain why this has occurred. ‘Food security is really only an issue for developing countries.’ Evaluate this statement. Compare how humans and fungi digest food. Why can tractors threaten food security? Does water that comes from reverse osmosis taste the same as tap water? Trophic levels in an ecosystem (biology): Why is the biomass of a secondary consumer population less than the primary consumer population? How many apex predators can you name? Evaluate the benefits of a vegetarian diet compared to a carnivorous diet in relation to transfer of biomass. How would a vegan diet compare to a vegetarian diet in relation to transfer of biomass? Farming and fishing: Research Blue Tongue Virus. Why does this threaten food security? Explain why BTV was not a concern in the UK until recently. Evaluate the advantages and disadvantages of intensive modern farming methods. Describe two fishing techniques which may promote the recovery of fish stocks. How do you feel about antibiotics being used in large amounts in fisheries and farming? Explain your reasoning.